1. Field of the Invention.
The present invention relates to protective screens for exhaust systems for internal combustion engines.
2. Description of the Prior Art.
It sometimes happens that the gases passing through the exhaust duct of the internal combustion engine of a motor vehicle reach a very high temperature which can be of the order of 600.degree.C. This is the case, in particular, of rotary engines at the exhaust of which a post-combustion device is provided to reduce the carbon monoxide content of the combustion gases whereby to prevent air pollution.
It has been proposed to protect the body of the vehicle by means of a refractory screen interposed between the body and the exhaust duct. If it is also desired to protect the ground, for example to prevent, if the vehicle is moving over grassy ground, the burning of the grass, this cannot be effected simply by interposing a refractory screen under the exhaust duct. Indeed, such a screen would then form with the body-protecting screen, a substantially closed sheath which would prevent the dissipation of heat by convection. Moreover, this screen would quickly be heated to a high temperature which, in turn, would cause the grass to burn.